Question

If $f$ is a real valued function defined by $f\left(x\right)=x^3+4x+3$, then fins $f^{\prime }\left(1\right)$ and $f^{\prime }\left(3\right)$.

Answer 1

f(x)=$x^3+4x+3$

f(a)=$3x^2+4$---(1)

then

f'(1)=3(1)+4=7

f'(3)=3(a)+4=27+4=31